This project involved evaluating approximately 800 existing bridges over waterways subject to scour, to determine their vulnerability to floods and whether they are scour vulnerable. This assessment was performed by an interdisciplinary team which included engineers and technicians with backgrounds in structural, geotechnical, and hydraulic engineering. This project was divided into four phases:

Phase I: Initial Scour Screening

Phase II: Scour Analysis of Bridges Determined to be Scour Susceptible

Phase III: Bridge Foundation Analysis using Calculated Scour Depths

Phase IV: Design of Retrofit Procedures

Modjeski and Masters provided engineering services to complete the scour screenings, scour analysis, structural analysis, and design of retrofits for the existing bridges. These tasks were performed using the criteria and procedures described in the following documents:

• HEC 18 - Evaluating Scour at Bridges
• HEC 20 - Stream Stability at Highway Structures
• FHWA’s Underwater Inspection of Bridges
• Recording and Coding Guide for the Structural Inventory and Appraisal of the Nation’s Bridges